Hello,
Thank you for posting in Q&A forum.
I recommend shutting down the VM, opening PowerShell on the host as an administrator, and running the following command. Replace "TestVm" with your vm name.
Set-VMVideo -VMName "TestVm" -HorizontalResolution 2560 -VerticalResolution 1440 -ResolutionType Single
I recommend you refer to the following link:
https://learn.microsoft.com/en-us/powershell/module/hyper-v/set-vmvideo?view=windowsserver2019-ps
I hope the information above is helpful.
Best regards
Zunhui
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